Ultrasound diagnostic equipment

Abstract

To set a gain suitable for a circuit that executes processing for a reflection wave signal in an ultrasonic diagnostic device.SOLUTION: An ultrasonic diagnostic device includes an ultrasonic probe, a plurality of detection units, a measurement unit, and a control unit. The ultrasonic probe having a plurality of vibrators transmits an ultrasonic signal to a subject by each of the vibrators, and receives, by each of the vibrators, a reflection wave signal which has returned after the transmitted ultrasonic signal is reflected by the inside of the subject. Each of the plurality of detection units corresponds to each of the vibrators, and detects the reflection wave signal that the corresponding vibrator receives. The measurement unit can measure a reflection wave signal larger than an amplitude that at least one detection unit is saturated when determining a gain of at least one detection unit of the plurality of detection units. The control unit obtains a gain on the basis of the reflection wave signal measured by the measurement unit, and controls the setting of the gain for the detection unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed in this specification and the drawings relate to an ultrasound diagnostic device. [Background technology]

[0002] Ultrasound diagnostic devices equipped with ultrasound probes have been known for some time. In ultrasound diagnostic devices, an ultrasound probe transmits an ultrasound signal, which is reflected back from the body of a subject (patient) and received by the ultrasound probe as a reflected wave signal. In ultrasound diagnostic devices, the analog reflected wave signal received by the ultrasound probe is processed by analog circuits such as amplifier circuits and filter circuits, then converted into a digital signal by an analog-to-digital converter (AD converter), and digitally processed to generate an image to be presented to the examiner (e.g., a doctor).

[0003] In an ultrasound diagnostic device, if an analog signal in any of the analog circuits becomes saturated, the quality of the image displayed will deteriorate. For this reason, an ultrasound diagnostic device sets a gain for each analog circuit so that the reflected wave signal does not become saturated. However, lowering the gain to prevent the reflected wave signal from becoming saturated can cause a deterioration in the signal-to-noise ratio (S / N) of the reflected wave signal. Therefore, an ultrasound diagnostic device must set an appropriate gain so that the reflected wave signal does not become saturated and the S / N ratio does not deteriorate.

[0004] In this regard, methods for detecting saturation of a reflected wave signal based on a signal after AD conversion and methods for switching the gain of an amplifier circuit based on the level of an input signal (i.e., a reflected wave signal) to the amplifier circuit are known. However, these conventional methods do not fully consider setting an appropriate gain for a circuit that processes a reflected wave signal in an ultrasound diagnostic apparatus. More specifically, a method for detecting saturation of a reflected wave signal based on a signal after AD conversion cannot detect which analog circuit up to the AD converter has saturation. A method for switching the gain of an amplifier circuit based on the level of an input signal to the amplifier circuit cannot detect saturation if saturation occurs in any analog circuit after the first amplifier circuit in the analog circuit.

[0005] Furthermore, recent ultrasound diagnostic devices often incorporate components that integrate everything from analog circuits to AD converters, making it even more difficult to detect in which analog circuit the reflected wave signal is saturated. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-076232 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-201110 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the embodiments disclosed in this specification and the drawings is to set an appropriate gain in a circuit that processes reflected wave signals in an ultrasound diagnostic device. However, the problem to be solved by the embodiments disclosed in this specification and the drawings is not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0008] An ultrasound diagnostic device according to an embodiment includes an ultrasound probe, multiple detectors, a measuring unit, and a control unit. The ultrasound probe includes multiple transducers, each of which transmits an ultrasound signal toward a subject, and each transducer receives a reflected wave signal that is returned after being reflected by the subject's body. Each of the multiple detectors corresponds to a corresponding transducer, and detects the reflected wave signal received by the corresponding transducer. The measuring unit includes: When determining the gain of at least one of the plurality of detectors, the amplitude is set to be greater than the amplitude at which the at least one detector is saturated. The reflected wave signal is measured. The control unit controls the setting of a gain for the detection unit. Each of the detection units has at least a first amplifier circuit and a second amplifier circuit. The first amplifier circuit amplifies the reflected wave signal and outputs a first detection signal. The second amplifier circuit receives the signal output by the first amplifier circuit. The first detection Signal moreover amplification The second detection signal is output. do. The measurement unit includes a third amplifier circuit and a first analog-to-digital converter. The third amplifier circuit measures the reflected wave signal, amplifies it, and outputs a first measurement signal. The first analog-to-digital converter converts the first measurement signal into a first digital signal. The control unit First digital signal Based on asked for , First gain the first amplifier circuit Set in Determined, The second gain the second amplifier circuit Set in Determine. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of an ultrasound diagnostic apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the configuration related to the measurement operation of gain adjustment in the ultrasound diagnostic apparatus according to the embodiment. [Figure 3] FIG. 2 is a diagram showing an example of the functional configuration of a control unit included in the ultrasound diagnostic apparatus according to the embodiment. [Figure 4] 6 is a flowchart showing an example of a processing flow in a control unit included in the ultrasound diagnostic apparatus according to the embodiment. [Figure 5] 10 is a flowchart showing another example of the flow of processing in the control unit included in the ultrasound diagnostic apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An ultrasound diagnostic apparatus according to an embodiment will be described below with reference to the drawings. The ultrasound diagnostic apparatus transmits an ultrasound signal from an ultrasound probe, and receives the ultrasound signal (reflected wave signal) that is reflected back from the body of a subject (patient) using the ultrasound probe. The ultrasound diagnostic apparatus detects the reflected wave signal received by the ultrasound probe, performs analog signal processing on the detected analog reflected wave signal using an analog circuit, and then converts the analog signal into a digital signal using an analog-to-digital converter (AD converter). The ultrasound diagnostic apparatus performs digital processing on the digital signal using a signal processing circuit to generate an ultrasound image based on the magnitude of the reflected wave signal, and presents the generated ultrasound image to the person conducting the examination (e.g., a doctor). This allows the person conducting the examination to visually confirm the condition of the tissue inside the subject's body.

[0011] 1 is a diagram illustrating the configuration of an ultrasound diagnostic apparatus according to an embodiment. The ultrasound diagnostic apparatus 1 includes, for example, an ultrasound probe 10, a main unit 20, an input unit 250, and a display unit 260. While FIG. 1 illustrates a configuration in which the input unit 250 and the display unit 260 are connected to the main unit 20, the input unit 250 and the display unit 260 may be incorporated into the main unit 20.

[0012] The ultrasonic probe 10 is used in contact with or in close proximity to the body of a subject. The ultrasonic probe 10 emits ultrasonic signals that are directional toward the body of the subject, receives reflected wave signals, and outputs the signals to the main unit 20. The ultrasonic probe 10 includes a plurality of ultrasonic transducers 12. The ultrasonic transducers 12 are, for example, piezoelectric elements such as piezoelectric ceramics. The ultrasonic probe 10 further includes a matching layer provided on each of the ultrasonic transducers 12, and a backing material that prevents ultrasonic signals from propagating rearward from the ultrasonic transducers 12 (toward the opposite side from the subject). The ultrasonic probe 10 may be detachable from the main unit 20. The plurality of ultrasonic transducers 12 are arranged in the ultrasonic probe 10 in any arrangement, such as a line or a two-dimensional array.

[0013] The main device 20 generates an ultrasound image based on the reflected wave signal output by the ultrasound probe 10. The main device 20 includes, for example, a transmission / reception circuit 21, a signal processing unit 22, a processing circuit 23, a memory circuit 24, an input interface 25, an output interface 26, and a communication interface 27.

[0014] The transmission / reception circuit 21 is controlled by the system control function of the processing circuit 23 or the signal processing unit 22, and supplies drive signals to the ultrasonic probe 10, detects and measures reflected wave signals output by the ultrasonic probe 10, and performs various signal processing on the reflected wave signals. The transmission / reception circuit 21 outputs detection signals generated by the various signal processing to the signal processing unit 22. The transmission / reception circuit 21 includes, for example, a pulser 212, a detection unit 214, a measurement unit 216, and a control unit 218.

[0015] The pulser 212 is a transmission circuit that supplies (applies voltage to) a drive signal (transmission pulse) to the ultrasonic transducer 12 included in the ultrasonic probe 10. The pulser 212 supplies a drive signal for each channel. For example, the pulser 212 generates a rectangular drive signal corresponding to a pulse signal repeatedly generated at a frequency based on a clock signal output by the processing circuit 23, converts the generated drive signal into a voltage for driving the ultrasonic transducer 12, and supplies the voltage to the ultrasonic probe 10. This causes the ultrasonic transducer 12 of the ultrasonic probe 10 to transmit an ultrasonic signal. The pulser 212 includes, for example, a pair of MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) in a complementary configuration, and an isolation diode connected in series to each MOSFET.

[0016] The detection unit 214 is a receiving circuit that detects reflected wave signals output by the ultrasound probe 10 during normal detection operations in the ultrasound diagnostic device 1. The detection unit 214 performs various signal processing on the detected reflected wave signals for each channel to generate digital signals representing the magnitude of the detected reflected wave signals, and outputs the digital signals as detection signals to the signal processing unit 22. The detection unit 214 uses predetermined parameters when performing various signal processing, but these can also be set, i.e., changed, by the control unit 218. The detection unit 214 includes, for each channel, components such as a transmit / receive separation switch (hereinafter referred to as "TRSW") 2141, an analog circuit, and an AD converter (hereinafter referred to as "detection ADC") 2146.

[0017] The TRSW2141 switches the output destination of the received reflected wave signal to an analog circuit during a period when it is expected to receive the reflected wave signal (hereinafter referred to as the "reception period"). The reception period is the time required for the ultrasonic signal transmitted by the ultrasonic transducer 12 in the ultrasonic probe 10 to be received as a reflected wave signal reflected by the tissue at the deepest part of the body of the subject for which an ultrasonic image is to be generated.

[0018] The analog circuit performs analog signal processing on the reflected wave signal output by the TRSW 2141 so that a reflected wave signal of an appropriate signal level is input to the detection ADC 2146. More specifically, the analog circuit performs gain correction on the reflected wave signal output by the TRSW 2141 so that the detection ADC 2146 can convert the reflected wave signal into a digital signal with effective resolution by making maximum use of the dynamic range during analog-to-digital conversion. The analog circuit includes, for example, components such as a low noise amplifier circuit (hereinafter referred to as "LNA") 2142, a variable gain amplifier circuit (hereinafter referred to as "VGA") 2143, a programmable amplifier circuit (hereinafter referred to as "PGA") 2144, and a low pass filter (hereinafter referred to as "LPF") 2145.

[0019] The LNA 2142 amplifies the amplitude of the reflected wave signal output by the TRSW 2141 with low noise based on a set gain. The gain of the LNA 2142 is fixed, but can be set or changed by the control unit 218. The LNA 2142 outputs the amplified reflected wave signal to the VGA 2143 as an LNA amplified signal. The LNA 2142 is an example of a "first amplifier circuit" in the claims, and the LNA amplified signal is an example of a "first detection signal" in the claims.

[0020] The VGA 2143 further amplifies the LNA-amplified signal output by the LNA 2142 with a gain that varies depending on the time the reflected signal is received. The strength and reception time of the reflected signal vary depending on the location (depth) of the tissue within the subject's body that reflects the ultrasound signal. That is, a reflected signal from tissue located shallow within the subject's body has high strength and a short reception time, while a reflected signal from tissue located deep within the subject's body has low strength and a long reception time. Furthermore, the reflected signal's frequency attenuation coefficient varies depending on the composition of the tissue (biological tissue) that reflects the ultrasound signal. The VGA 2143 amplifies the reflected signal (LNA-amplified signal) with different reception times and attenuation coefficients based on a gain curve that is set according to the tissue and composition. The VGA 2143 is also known as a time gain control (TGC) amplifier circuit. The gain curve of the VGA 2143 is a fixed gain curve determined for each tissue and composition of a living body, but can be corrected, or more specifically, offset, by the control unit 218. The VGA 2143 outputs the amplified reflected wave signal as a VGA amplified signal to the PGA 2144. The VGA 2143 is an example of a "second amplifier circuit" in the claims, and the VGA amplified signal is an example of a "second detection signal" in the claims.

[0021] The PGA 2144 further amplifies the signal amplified by the VGA 2143 based on a set gain. The gain of the PGA 2144 is switched depending on the state of the examination in the ultrasound diagnostic apparatus 1, such as the operation mode of the ultrasound diagnostic apparatus 1, the part of the subject being examined in the ultrasound diagnostic apparatus 1, and the configuration of the ultrasound probe 10 connected to the ultrasound diagnostic apparatus 1. The PGA 2144 outputs the amplified reflected wave signal to the LPF 2145 as a PGA amplified signal.

[0022] The LPF 2145 attenuates components above a certain frequency in the PGA-amplified signal output by the PGA 2144. The LPF 2145 attenuates high-frequency components included in the PGA-amplified signal according to the sampling frequency used when the detection ADC 2146 performs analog-to-digital conversion. In other words, the LPF 2145 attenuates, for example, reflected wave signals above the Nyquist frequency included in the PGA-amplified signal so that reflected wave signals with frequencies exceeding the sampling frequency of the detection ADC 2146 are not input to the detection ADC 2146 as high-frequency noise or aliasing noise. The LPF 2145 is also called an anti-alias filter (AAF). The LPF 2145 outputs the reflected wave signal, from which high-frequency components have been attenuated, to the detection ADC 2146 as an LPF-attenuated signal.

[0023] The detection ADC 2146 converts the analog signal that has been subjected to analog signal processing by the analog circuit into a digital signal. In other words, the detection ADC 2146 performs analog-to-digital conversion on the LPF-attenuated signal output by the LPF 2145 to generate a digital signal that represents the magnitude of the reflected wave signal. The detection ADC 2146 outputs the generated digital signal to the signal processing unit 22 as a detection signal. The detection ADC 2146 is an example of a "second analog-to-digital converter" in the claims, and the detection signal is an example of a "second digital signal" in the claims.

[0024] The measurement unit 216 is a receiving circuit that measures the reflected wave signal output by the ultrasonic probe 10 during the measurement operation for gain adjustment in the ultrasonic diagnostic apparatus 1. The measurement unit 216 is provided for several channels near the center where the ultrasonic probe 10 is expected to receive reflected wave signals with high signal levels. The measurement unit 216 is provided in parallel to the detection unit 214 corresponding to the multiple ultrasonic transducers 12 arranged in the center of the ultrasonic probe 10. Here, the reflected wave signal measured by the measurement unit 216 is a reflected wave signal that is an ultrasonic signal transmitted during the gain adjustment operation in the ultrasonic diagnostic apparatus 1 and reflected inside the body of the subject and returns. The reflected wave signal measured by the measurement unit 216 is a reflected wave signal with the same amplitude as the reflected wave signal output by the ultrasonic probe 10 during normal detection operation in the ultrasonic diagnostic apparatus 1. In the following description, in order to distinguish between the reflected wave signal detected by the detection unit 214 and the reflected wave signal measured by the measurement unit 216, the reflected wave signal measured by the measurement unit 216 will be referred to as a "measurement reflected wave signal." The measurement unit 216 amplifies the measured reflected wave signal for measurement, generates a digital signal representing the magnitude of the amplified reflected wave signal for measurement, and outputs the measurement signal to the control unit 218. The measurement unit 216 includes components such as a changeover switch 2162, an amplifier circuit (hereinafter referred to as a "measurement AMP") 2164, and an AD converter (hereinafter referred to as a "measurement ADC") 2166, for example.

[0025] The selector switch 2162 switches the connection of a signal line (hereinafter referred to as an "input signal line") that inputs a reflected wave signal to the measurement AMP 2164 in response to control from the control unit 218. The selector switch 2162 connects the signal line (hereinafter referred to as an "output signal line"), through which the TRSW 2141 of the corresponding detection unit 214 outputs a reflected wave signal, to the input signal line so that the measurement reflected wave signal is input to the measurement AMP 2164 during measurement operation for gain adjustment. On the other hand, the selector switch 2162 separates (disconnects) the output signal line from the input signal line so that the measurement reflected wave signal is not input to the measurement AMP 2164 during operations other than measurement operation for gain adjustment, such as normal detection operation. At this time, the selector switch 2162 connects the input signal line to a ground signal line so that, for example, a ground-level signal is input to the measurement AMP 2164. The selector switch 2162 is an example of a "switching circuit" in the claims. An operation such as a normal detection operation is an example of a "first operation" in the claims, and a measurement operation for gain adjustment is an example of a "second operation" in the claims.

[0026] The measurement AMP 2164 amplifies the amplitude of the measurement reflected wave signal input via the selector switch 2162 based on a predetermined gain. The measurement AMP 2164 is an amplifier circuit with a large (wide) maximum input amplitude that can be amplified. The measurement AMP 2164 amplifies the amplitude of the input measurement reflected wave signal to an amplitude that can be input to the measurement ADC 2166. The gain of the measurement AMP 2164 is equal to or lower than the gain of the LNA 2142 provided in the detection unit 214. The measurement AMP 2164 outputs the amplified measurement reflected wave signal to the measurement ADC 2166 as an AMP-amplified signal. The measurement AMP 2164 is an example of a "third amplifier circuit" in the claims, and the AMP-amplified signal is an example of a "first measurement signal" in the claims.

[0027] The measurement ADC 2166 performs analog-to-digital conversion on the AMP-amplified signal output by the measurement AMP 2164 to generate a digital signal representing the magnitude of the measurement reflected wave signal. The measurement ADC 2166 outputs the generated digital signal to the control unit 218 as a measurement signal. The measurement ADC 2166 may have a larger dynamic range or higher resolution than the detection ADC 2146. The measurement ADC 2166 is an example of a "first analog-to-digital converter" in the claims, and the measurement signal is an example of a "first digital signal" in the claims.

[0028] In the measurement operation for gain adjustment in the ultrasonic diagnostic apparatus 1, the control unit 218 determines a gain to be set in each amplifier circuit in the analog circuit included in the detection unit 214 based on the measurement signal output by the measurement unit 216. The control unit 218 sets the determined gain in each corresponding amplifier circuit. More specifically, the control unit 218 determines a gain to be set in the LNA 2142 and a gain to be set in the VGA 2143 included in the detection unit 214, more specifically, an offset value for offsetting (correcting) the gain curve, and sets these in the LNA 2142 and the VGA 2143. The start of the measurement operation for gain adjustment in the ultrasonic diagnostic apparatus 1 is instructed by, for example, the processing circuit 23 or the input interface 25. The gain to be set in the LNA 2142 is an example of a "first gain" in the claims, and the gain to be set in the VGA 2143 is an example of a "second gain" in the claims.

[0029] During normal detection operation in the ultrasound diagnostic apparatus 1, the control unit 218 monitors whether or not saturation occurs in the detection signals output by the detection ADCs 2146 of all channels. At this time, the control unit 218 acquires the detection signals output by all the detection ADCs 2146 from the signal processing unit 22. The control unit 218 then analyzes the acquired detection signals to monitor whether or not saturation occurs in the detection signals. If the control unit 218 determines that saturation has occurred in the detection signals, it outputs information indicating this to the processing circuitry 23. This enables the processing circuitry 23 to notify the person conducting the examination to urge them to perform gain adjustment. In response to this notification, the control unit 218 receives an instruction to start a measurement operation for gain adjustment from, for example, the processing circuitry 23 or the input interface 25, and then performs the measurement operation for gain adjustment again to determine the gains to be set for the LNA 2142 and the VGA 2143. In response to an instruction to start the measurement operation for gain adjustment, the control unit 218 may set a gain for each of the LNA 2142 and the VGA 2143 that is changed by, for example, a predetermined gain value previously set by the person performing the examination or a predetermined gain value previously set (preset) in the ultrasound diagnostic apparatus 1.

[0030] Fig. 2 is a diagram showing an example of the configuration related to the measurement operation of gain adjustment in the ultrasound diagnostic device 1 according to the embodiment. Fig. 2 shows an example of the configuration of the ultrasound diagnostic device 1 to which an N-channel ultrasound probe 10 is connected. Therefore, in the ultrasound diagnostic device 1 shown in Fig. 2, a pulser 212 and a detection unit 214 are connected to the ultrasound transducer 12 of each channel. Fig. 2 also shows the connections of the respective components of the detection unit 214, namely, a TRSW 2141, an LNA 2142, a VGA 2143, a PGA 2144, an LPF 2145, and a detection ADC 2146.

[0031] 2, each channel (channels CH-1 to CH-N) in the ultrasound diagnostic device 1 is clearly indicated. In FIG. 2, for each channel, the number or letter following the "- (hyphen)" after the symbol "CH" indicates the channel number.

[0032] In the ultrasonic diagnostic apparatus 1 shown in Fig. 2, a measurement unit 216 is provided for several channels (channels CH-L to CH-M) near the center. Fig. 2 also shows the connections between the components of the changeover switch 2162, measurement AMP 2164, and measurement ADC 2166 provided in the measurement unit 216.

[0033] 2, the control unit 218 determines and sets the gain to be set in the amplifier circuit in the analog circuit provided in each of the detection units 214 of channels CH-1 to CH-N based on the measurement signals output by the measurement units 216 of channels CH-L to CH-M. Although the ultrasonic diagnostic device 1 shown in Fig. 2 shows a configuration in which one control unit 218 corresponds to each of the measurement units 216 of channels CH-L to CH-M, the control unit 218 may be provided as a component in each of the measurement units 216, and the measurement units 216 provided in each of the measurement units 216 may work together to determine and set the gain to be set in each of the amplifier circuits.

[0034] 3 is a diagram showing an example of the functional configuration of the control unit 218 included in the ultrasound diagnostic apparatus 1 according to the embodiment. The control unit 218 executes, for example, a signal measurement function 2181, a maximum value detection function 2182, a gain calculation function 2183, a gain control function 2184, and a saturation monitoring function 2185. The control unit 218 realizes these functions by, for example, causing a hardware processor to execute a program stored in a storage device (for example, the storage circuitry 24).

[0035] A hardware processor refers to a circuit such as a central processing unit (CPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), or a programmable logic device (e.g., a simple programmable logic device (SPLD) or a complex programmable logic device (CPLD), or a field programmable gate array (FPGA)). Instead of storing a program in a memory device, a hardware processor may be configured so that the program is directly embedded in the circuit. In this case, the hardware processor performs its functions by reading and executing the program embedded in the circuit. A hardware processor is not limited to a single circuit, but may be configured as a single hardware processor by combining multiple independent circuits to perform each function. A memory device may be a non-transitory (hardware) storage medium. Multiple components may be integrated into a single hardware processor to perform each function. Multiple components may be integrated into a single dedicated LSI to perform each function. Here, the program (software) may be stored in advance in a storage device (a storage device having a non-transitory storage medium) that constitutes a storage device such as a semiconductor memory element such as a ROM (Read Only Memory), a RAM (Random Access Memory), or a flash memory, or a hard disk drive (HDD), or may be stored in a removable storage medium (a non-transitory storage medium) such as a DVD or CD-ROM, and installed in a storage device provided in the main unit 20 by inserting the storage medium into a drive device provided in the main unit 20.The program (software) may be downloaded in advance from another computer device via a network and installed in a storage device provided in main device 20. The program (software) installed in the storage device provided in main device 20 may be transferred to a storage device provided in control unit 218 and executed therein.

[0036] In the measurement operation of gain adjustment, the signal measurement function 2181 switches each changeover switch 2162 so that the measurement reflected wave signal is input to the measurement AMP 2164, sets the gain of the LNA 2142 to the maximum gain (hereinafter referred to as "LNA maximum gain"), and causes the pulser 212 to transmit a measurement ultrasonic signal. Then, the signal measurement function 2181 operates each measurement AMP 2164 and measurement ADC 2166 to acquire, from each measurement unit 216, a measurement signal (digital signal) representing the magnitude of the measurement reflected wave signal within the reception period output by the TRSW 2141. The signal measurement function 2181 may store each acquired measurement signal, for example, in a storage device provided in the control unit 218, or in the memory circuit 24.

[0037] After acquiring the measurement signal from the measurement unit 216 or when the measurement operation for gain adjustment is completed, the signal measurement function 2181 switches each changeover switch 2162 so that the measurement reflected wave signal is not input to the measurement AMP 2164.

[0038] The maximum value detection function 2182 detects the maximum value of the measurement reflected wave signal based on each measurement signal acquired by the signal measurement function 2181. The maximum value of the measurement reflected wave signal detected by the maximum value detection function 2182 corresponds to the maximum value of the reflected wave signal that may be input to the detection unit 214, i.e., the LNA 2142, during normal detection operation in the ultrasound diagnostic device 1. In the following description, the maximum value of the measurement reflected wave signal detected by the maximum value detection function 2182 is referred to as the "LNA input maximum value." The LNA input maximum value is an example of a "first maximum value" in the claims.

[0039] Furthermore, the maximum value detection function 2182 assumes that the gain calculated by the gain calculation function 2183 to be set in the LNA 2142 is set in the LNA 2142, and in this state, calculates an output signal from the LNA 2142 when the detected maximum LNA input value is input, and multiplies the output signal thus calculated by a gain curve scheduled for amplification by the VGA 2143 to calculate the maximum value of the output signal output by the VGA 2143. The scheduled gain curve is a gain curve with an initial value (which may be a reference value) that matches the tissue and composition inside the subject's body. Information about the scheduled gain curve may be stored in a storage device included in the control unit 218, for example, or may be obtained from the storage circuitry 24 based on information about the gain curve to be set in the VGA 2143, which is acquired from the processing circuitry 23 or specified. The output signal of the LNA 2142 determined by the maximum value detection function 2182 is output after a reflected wave signal corresponding to the maximum LNA input value is input to the LNA 2142 and amplified during normal detection operation. In other words, it is a signal corresponding to the maximum LNA amplified signal output when the maximum LNA input value passes through the LNA 2142. The maximum value of the output signal of the VGA 2143 determined by the maximum value detection function 2182 corresponds to the maximum value of a VGA amplified signal that may be output by the VGA 2143 when the maximum LNA amplified signal is input during normal detection operation. In other words, it corresponds to the maximum value of an input signal that may be input to the PGA 2144. In the following description, the output signal of the LNA 2142 when the maximum LNA input value determined by the maximum value detection function 2182 passes through is referred to as the "LNA passing maximum value," and the maximum value of the output signal of the VGA 2143 determined by the maximum value detection function 2182 is referred to as the "VGA output maximum value." The VGA output maximum value is an example of a "second maximum value" in the claims.

[0040] The gain calculation function 2183 calculates the maximum gain of the LNA 2142 that can pass the maximum LNA input value detected by the maximum value detection function 2182. In this case, the maximum gain of the LNA 2142 calculated by the gain calculation function 2183 is the LNA maximum gain or a gain lower than the LNA maximum gain. In the following description, the maximum gain of the LNA 2142 calculated by the gain calculation function 2183 is referred to as the "LNA maximum passing gain." The LNA maximum passing gain is an example of a "first gain" in the claims.

[0041] Furthermore, the gain calculation function 2183 calculates the gain of the VGA 2143 such that the VGA output maximum value found by the maximum value detection function 2182 becomes the maximum value of the VGA amplified signal output by the VGA 2143. In other words, the gain calculation function 2183 calculates the gain of the VGA 2143 such that the VGA output maximum value becomes the maximum value of the input signal that can be input to the PGA 2144 (in other words, the limit value of the input signal to the PGA 2144). The maximum value of the input signal that can be input to the PGA 2144 may be stored in a storage device provided in the control unit 218, for example, as information on the maximum value based on a standard value of the PGA 2144, or may be acquired or specified from the processing circuitry 23 depending on the state of examination in the ultrasound diagnostic apparatus 1. Then, based on the gain curve of the VGA 2143, the gain calculation function 2183 calculates an offset value of the gain curve such that the gain at the time when the amplified and output VGA amplified signal becomes the calculated gain of the VGA 2143. In the following description, the offset value of the gain curve of the VGA 2143 calculated by the gain calculation function 2183 is referred to as a "VGA gain offset." The VGA gain offset is an example of a "second gain" in the claims.

[0042] The gain control function 2184 sets the LNA maximum pass gain calculated by the gain calculation function 2183 to the LNA 2142 as the gain of the LNA 2142. Furthermore, the gain control function 2184 offsets (corrects) the gain curve of the VGA 2143 with the VGA gain offset calculated by the gain calculation function 2183.

[0043] In normal detection operation, the saturation monitoring function 2185 acquires detection signals output by all detection ADCs 2146 from the signal processing unit 22, analyzes the acquired detection signals, and monitors whether or not saturation has occurred in the detection signals output by the detection ADCs 2146 of all channels. The saturation monitoring function 2185 monitors whether or not saturation has occurred in the detection signals, for example, by analyzing the waveform of the acquired detection signals on the time axis, and determines that saturation has occurred in the detection signals if the signal level of any of the detection signals remains at its upper limit for a predetermined period of time or longer. The saturation monitoring function 2185 monitors whether or not saturation has occurred in the detection signals, for example, by performing frequency analysis on the acquired detection signals, and determines that saturation has occurred in the detection signals if the rise in the third harmonic of any of the detection signals relative to the fundamental wave is equal to or greater than a predetermined level. The method of determining (detecting) whether or not saturation has occurred in the detection signals in the saturation monitoring function 2185 is not limited to the above-described method, and may be any method suitable for the state of examination in the ultrasound diagnostic apparatus 1. If the saturation monitoring function 2185 determines that saturation has occurred in any of the detection signals, it outputs information indicating this to the processing circuit 23.

[0044] By performing these functions, the control unit 218 adjusts the gains of the LNA 2142 and VGA 2143 included in the detection unit 214 during measurement operation for gain adjustment in the ultrasonic diagnostic apparatus 1. As a result, the detection ADC 2146 can make full use of the dynamic range and output a detection signal obtained by analog-to-digital conversion of the LPF-attenuated signal output by the LPF 2145 to the signal processing unit 22. Furthermore, the control unit 218 determines whether saturation has occurred in the detection signal output by the detection ADC 2146 of any channel during normal detection operation in the ultrasonic diagnostic apparatus 1. As a result, in the ultrasonic diagnostic apparatus 1, if saturation has occurred in any detection signal, the gains of the LNA 2142 and VGA 2143 included in the detection unit 214 can be readjusted. Details of the gain adjustment in the control unit 218 and the processing for monitoring whether or not saturation has occurred in the detection signal will be described later.

[0045] 1, the signal processing unit 22 performs image processing to generate an ultrasound image that visualizes the state of tissue inside the subject's body based on the detection signal output by the detection unit 214 included in the transmission / reception circuit 21. The image processing method in the signal processing unit 22 is not particularly specified. The signal processing unit 22 outputs the generated ultrasound image to the output interface 26 or stores it in the memory circuit 24. The signal processing unit 22 outputs the detection signal output by the detection unit 214 to the control unit 218 so that the control unit 218 can monitor saturation of the detection signal. The signal processing unit 22 may output the generated ultrasound image to the control unit 218 so that the control unit 218 can monitor saturation of the detection signal.

[0046] The processing circuitry 23 controls the overall operation of the ultrasound diagnostic apparatus 1. The processing circuitry 23 executes, for example, a system control function (not shown). The processing circuitry 23 realizes the system control function (not shown), for example, by a hardware processor executing a program (software) stored in a storage device (for example, the storage circuitry 24). As with the control unit 218, the hardware processor of the processing circuitry 23 refers to a circuit such as a CPU, a GPU, an application-specific integrated circuit, or a programmable logic device. The processing circuitry 23 executes the system control function (not shown) and controls various operations in the ultrasound diagnostic apparatus 1, for example, based on an input operation by the examiner received by the input interface 25. More specifically, when the examiner performs an input operation to perform gain adjustment via the input interface 25, the processing circuitry 23 instructs the control unit 218 to start a measurement operation for gain adjustment.

[0047] The memory circuitry 24 is realized by, for example, a semiconductor memory element such as a ROM, a RAM, or a flash memory, a hard disk drive, an optical disk, etc. The memory circuitry 24 stores setting data of the components included in the transmission / reception circuitry 21 (for example, a gain curve of the VGA 2143), the control unit 218 (more specifically, data of a measurement signal acquired by a signal measurement function 2181 included in the control unit 218), data of an ultrasound image output by the signal processing unit 22, etc. The memory circuitry 24 may store in advance programs to be executed by the control unit 218 and the processing circuitry 23.

[0048] The input interface 25 accepts various input operations by the examiner using the ultrasound diagnostic apparatus 1. The input interface 25 accepts input operations performed by the examiner using an input device 250, such as a mouse, keyboard, touch panel, trackball, switch, button, joystick, camera, infrared sensor, or microphone. The input interface 25 outputs information indicating the content of the accepted input operation to the processing circuitry 23. For example, when the examiner performs an input operation to perform gain adjustment, the input interface 25 accepts the input operation and outputs information indicating that gain adjustment has been requested to the processing circuitry 23. In this specification, the input interface 25 or the input device 250 is not limited to those having physical operating components such as a mouse or keyboard. For example, an example of the input interface 25 also includes an electrical signal processing circuit that receives an electrical signal corresponding to the input operation from an external input device provided separately from the main unit 20 and outputs the electrical signal to the processing circuitry 23.

[0049] The output interface 26 provides various types of information to the examiner using the ultrasound diagnostic apparatus 1. The output interface 26 displays, for example, the ultrasound image output by the signal processing unit 22 or the ultrasound image stored in the memory circuitry 24 by the signal processing unit 22 on a display device 260 such as a liquid crystal display (LCD), a CRT (cathode ray tube) display, or an organic EL (electroluminescence) display. This allows the examiner to check the state of the tissue inside the subject's body from the ultrasound image displayed on the display device 260. The output interface 26 may also display, on the display device 260, a GUI (Graphical User Interface) image or the like for receiving various input operations to the input interface 25 by the examiner.

[0050] The communication interface 27 communicates with an external device (not shown) connected via a network such as a local area network (LAN) established within a hospital. The external device is, for example, a database device such as a medical image management system (Picture Archiving and Communication Systems (PACS)) that manages data on various medical images, or an electronic medical record system that manages electronic medical records to which medical images such as ultrasound images from previous examinations performed by the ultrasound diagnostic device 1 are attached. The external device may also be, for example, another medical device located within the hospital, such as a computed tomography (CT) device or a magnetic resonance imaging (MRI) device.

[0051] Next, an example of the process of gain adjustment and detection signal monitoring in the control unit 218 will be described. Fig. 4 is a flowchart showing an example of the flow of the process in the control unit 218 included in the ultrasound diagnostic apparatus 1 according to this embodiment. The process of this flowchart is repeatedly executed while the ultrasound diagnostic apparatus 1 is running.

[0052] When the ultrasound diagnostic apparatus 1 is started up, the control unit 218 checks whether there is an instruction to start a measurement operation for gain adjustment (step S100). Here, when the person conducting the examination operates the input device 250 to perform an input operation for performing gain adjustment while the ultrasound probe 10 is in contact with or close to the body of the subject, the input interface 25 accepts this input operation. Then, the processing circuitry 23 outputs an instruction to start a measurement operation for gain adjustment to the control unit 218 based on the information of the input operation indicating that gain adjustment will be performed, accepted by the input interface 25. If it is confirmed in step S100 that there is an instruction to start a measurement operation for gain adjustment, the control unit 218 starts the gain adjustment process.

[0053] When the gain adjustment process starts, the signal measurement function 2181 switches the selector switch 2162 to connect the input signal line of the measurement AMP 2164 to the output signal line of the corresponding TRSW 2141 (step S102). Subsequently, the signal measurement function 2181 sets the gain of the LNA 2142 to the maximum LNA gain and causes the pulser 212 to transmit a measurement ultrasonic signal (step S104). Then, the signal measurement function 2181 operates each measurement AMP 2164 and measurement ADC 2166 to acquire a measurement signal from each measurement unit 216 (step S106). The signal measurement function 2181 outputs each acquired measurement signal to the maximum value detection function 2182.

[0054] The maximum value detection function 2182 detects the maximum LNA input value within the reception period based on the measurement signal output by the signal measurement function 2181 (step S108). The maximum value detection function 2182 outputs information on the detected maximum LNA input value to the gain calculation function 2183.

[0055] The gain calculation function 2183 calculates the LNA maximum pass gain (step S110) based on the information on the maximum LNA input value output by the maximum value detection function 2182. The gain calculation function 2183 outputs the calculated information on the LNA maximum pass gain to both the maximum value detection function 2182 and the gain control function 2184.

[0056] The gain control function 2184 sets the LNA maximum pass gain output by the gain calculation function 2183 in the LNA 2142 (step S112).

[0057] The maximum value detection function 2182 calculates the maximum LNA passing value based on the information on the LNA maximum passing gain output by the gain calculation function 2183, and calculates the maximum VGA output value within the reception period by multiplying the calculated maximum LNA passing value by the expected gain curve of the VGA 2143 (step S114). The maximum value detection function 2182 outputs information on the calculated maximum VGA output value to the gain calculation function 2183.

[0058] The gain calculation function 2183 calculates the gain of the VGA 2143 such that the maximum VGA output value becomes the maximum input value of the PGA 2144 based on the information on the maximum VGA output value output by the maximum value detection function 2182, and calculates a VGA gain offset based on the calculated gain (step S116). The gain calculation function 2183 outputs the calculated VGA gain offset to the gain control function 2184.

[0059] The gain control function 2184 offsets the gain curve of the VGA 2143 based on the VGA gain offset information output by the gain calculation function 2183 (step S118).

[0060] The signal measurement function 2181 switches the selector switch 2162 to disconnect the connected input signal line of the measurement AMP 2164 from the corresponding output signal line of the TRSW 2141 (step S120). This ends the gain adjustment process in the control unit 218. At this time, the control unit 218 notifies the processing circuit 23 that the gain adjustment process has ended. This causes the processing circuit 23 to start a normal detection operation.

[0061] In step S100, if it is confirmed that there is no instruction to start the measurement operation for gain adjustment, or if a normal detection operation has started, the control unit 218 starts the process of monitoring the detection signal (step S200).

[0062] When the process of monitoring the detection signal starts, the saturation monitoring function 2185 acquires the detection signals output by the detection ADCs 2146 of all channels from the signal processing unit 22 (step S202). Then, the saturation monitoring function 2185 analyzes the acquired detection signals.

[0063] The saturation monitoring function 2185 checks whether saturation has occurred in any of the detection signals (step S204). If it is confirmed in step S204 that saturation has not occurred in any of the detection signals, the saturation monitoring function 2185 returns the process to step S100. As a result, if there is an instruction to start the measurement operation for gain adjustment, the control unit 218 performs the gain adjustment process (the process of steps S102 to S120) again, and if there is no instruction to start the measurement operation for gain adjustment, it continues the process of monitoring the detection signal for the next detection signal.

[0064] On the other hand, if it is determined in step S204 that saturation has occurred in any of the detection signals, the saturation monitoring function 2185 outputs (notifies) information indicating this to the processing circuit 23 (step S206). Then, the saturation monitoring function 2185 returns the process to step S100.

[0065] When the processing circuitry 23 is notified by the saturation monitoring function 2185 that saturation has occurred in the detection signal, it notifies the person conducting the test to urge them to perform gain adjustment. Then, in response to this notification, the person conducting the test operates the input device 250 to perform an input operation to perform gain adjustment, and the input interface 25 accepts this input operation, and the processing circuitry 23 outputs an instruction to start a measurement operation for gain adjustment to the control unit 218 based on the information on the input operation accepted by the input interface 25. This causes the control unit 218 to perform the gain adjustment process (the processes of steps S102 to S120) again.

[0066] Through this processing, in the ultrasonic diagnostic apparatus 1, the control unit 218 automatically adjusts the gain of the LNA 2142 and VGA 2143 included in the detection unit 214. As a result, in the ultrasonic diagnostic apparatus 1, the signal level is maximized within a range that does not saturate the reflected wave signal in the analog circuit included in the detection unit 214, and the detection ADC 2146 can output a detection signal (digital signal) indicating the magnitude of the reflected wave signal to the signal processing unit 22 by making full use of the dynamic range. As a result, in the ultrasonic diagnostic apparatus 1, signal saturation does not occur in the analog circuit involved in detecting the reflected wave signal, and deterioration of image quality is suppressed, and an ultrasonic image with a maximized S / N ratio can be generated. Moreover, in the ultrasonic diagnostic apparatus 1, the measurement unit 216, which is a component for automatically adjusting the gain, is not provided for the detection units 214 of all channels, but only for the detection units 214 of several channels near the center. As a result, the ultrasonic diagnostic apparatus 1 can automatically adjust the gain while suppressing increases in circuit size and power consumption.

[0067] Furthermore, in the ultrasound diagnostic device 1, the control unit 218 monitors whether or not saturation has occurred in the detection signals output by the detection ADCs 2146 included in the detection units 214 of all channels during normal detection operation. This makes it possible for the ultrasound diagnostic device 1 to detect saturation of the detection signals due to changes in the signal level of the reflected wave signals that may occur during an examination due to, for example, changes (movements) in the body position or tissues of the subject, or changes (movements) in the position of the ultrasound probe 10 that is in contact with or close to the body of the subject, and when saturation has been detected in any of the detection signals, it can notify the person conducting the examination to urge them to adjust the gain.

[0068] In an example of processing by the control unit 218 shown in FIG. 4 , in the gain adjustment process, the signal measurement function 2181 connects and disconnects the input signal line and the output signal line using the selector switch 2162. However, in the ultrasound diagnostic apparatus 1, various ultrasound probes 10 are connected to the main unit 20. Therefore, some ultrasound probes 10 connected to the main unit 20 for examination have impedances as the ultrasound probe 10, such as the impedance of the ultrasound transducer 12, that are lower than the impedance expected by the LNA 2142. Furthermore, even if the input signal line remains connected to the output signal line during normal detection operations in the ultrasound diagnostic apparatus 1, that is, even if the measurement AMP 2164 is always connected to the output signal line, there may be no effect such as a decrease in the signal level of the reflected wave signal received during normal detection, and noise due to signals other than those of a living body may not be generated in the generated ultrasound image. When such an ultrasound probe 10 is connected to the main unit 20, the control unit 218 can perform gain adjustment processing periodically, for example, once per predetermined frame. That is, the ultrasonic diagnostic apparatus 1 can automatically perform the gain adjustment process without requiring the examiner to perform an input operation for performing the gain adjustment.

[0069] Here, an example of the gain adjustment and detection signal monitoring processing in the control unit 218 in this case will be described. FIG. 5 is a flowchart showing another example of the processing flow in the control unit 218 included in the ultrasound diagnostic apparatus 1 according to this embodiment. In the flowchart shown in FIG. 5, the same step numbers are assigned to processes that are similar to the processes in the flowchart shown in FIG. 4. In processes assigned the same step numbers, only the different processing content will be described, and detailed descriptions of the same processing content will be omitted. The processing of this flowchart is also repeatedly executed while the ultrasound diagnostic apparatus 1 is running.

[0070] When the ultrasound diagnostic apparatus 1 is started, the control unit 218 checks whether there is an instruction to start a measurement operation for gain adjustment (step S100). The input operation by the examiner and the processing by the input interface 25 and processing circuit 23 at this time are the same as those described in the flowchart shown in FIG. 4. The processing of step S100 accepts the input operation for performing gain adjustment by the examiner; in other words, it is for the examiner to cause the ultrasound diagnostic apparatus 1 to perform the gain adjustment processing at a timing desired by the examiner. Therefore, for example, if the ultrasound diagnostic apparatus 1 performs gain adjustment automatically, the initial processing of step S100 may be omitted.

[0071] In step S100, when it is confirmed that there is an instruction to start the measurement operation for gain adjustment (this does not apply if the initial processing of step S100 is omitted), control unit 218 starts the gain adjustment processing. When the gain adjustment processing is started, the processing of control unit 218 is the same as the processing shown in the flowchart of FIG. 4, except that the processing of step S102 and the processing of step S120 are omitted.

[0072] In step S100, if it is confirmed that there is no instruction to start the measurement operation for gain adjustment, or if the gain adjustment process in control unit 218 has ended, processing circuit 23 starts a normal detection operation. Then, control unit 218 starts the process of monitoring the detection signal (step S200).

[0073] When the process of monitoring the detection signal starts, the control unit 218 checks whether a predetermined period of time has elapsed (step S300). If it is confirmed in step S300 that the predetermined period of time has elapsed, the control unit 218 returns the process to step S104 and performs the gain adjustment process (the processes of steps S104 to S118) again.

[0074] On the other hand, if it is determined in step S300 that the predetermined period has not elapsed, control unit 218 continues the process of monitoring the detection signal. The process of monitoring the detection signal is the same as the process shown in the flowchart of FIG. 4 (the process of steps S202 to S206).

[0075] Through this processing, in the ultrasonic diagnostic apparatus 1, the control unit 218 automatically and periodically adjusts the gain of the LNA 2142 and VGA 2143 included in the detection unit 214. As a result, in the ultrasonic diagnostic apparatus 1, the signal level is maximized within a range that does not saturate the reflected wave signal in the analog circuit included in the detection unit 214, and the detection ADC 2146 can output a detection signal (digital signal) representing the magnitude of the reflected wave signal to the signal processing unit 22 by making full use of the dynamic range. As a result, in the ultrasonic diagnostic apparatus 1, signal saturation does not occur in the analog circuit involved in detecting the reflected wave signal, and deterioration of image quality is suppressed, and an ultrasonic image with a maximized S / N ratio can be generated. Moreover, in the ultrasonic diagnostic apparatus 1, the measurement unit 216, which is configured to perform automatic gain adjustment, is provided only for the detection units 214 of several channels near the center, rather than for all the detection units 214 of the channels. As a result, the ultrasonic diagnostic apparatus 1 can automatically adjust the gain while suppressing increases in circuit size and power consumption.

[0076] Furthermore, in the ultrasound diagnostic apparatus 1, the control unit 218 monitors whether or not saturation has occurred in the detection signals output by the detection ADCs 2146 included in the detection units 214 of all channels during normal detection operation. Furthermore, the ultrasound diagnostic apparatus 1 automatically adjusts the gain of the LNAs 2142 and VGAs 2143 included in the detection units 214 at regular intervals. This allows the ultrasound diagnostic apparatus 1 to reduce the frequency of detection signal saturation due to changes in the signal level of reflected wave signals that may occur during an examination due to, for example, changes (movements) in the body position or internal tissues of the subject, or changes (movements) in the position of the ultrasound probe 10 that is in contact with or close to the subject's body. Furthermore, when the ultrasound diagnostic apparatus 1 detects that saturation has occurred in any of the detection signals, it can notify the person conducting the examination to prompt them to adjust the gain.

[0077] Some ultrasonic probes 10 receive and output reflected wave signals with a low maximum frequency. In this case, the control unit 218 can, for example, analyze the maximum frequency of the reflected wave signal or the measurement reflected wave signal output by the ultrasonic probe 10 using the saturation monitoring function 2185 and change the cutoff frequency of the LPF 2145 based on the results. In this case, the control unit 218 can minimize the frequency band of the LPF-attenuated signal output by the LPF 2145 to the detection ADC 2146 by, for example, setting the minimum value of the LPF 2145 to be at least twice the maximum frequency. This allows the LPF 2145 to output an LPF-attenuated signal to the detection ADC 2146, reducing the noise level of thermal noise (so-called white noise) included in the entire band of the reflected wave signal, and the detection ADC 2146 can output a measurement signal with an improved S / N ratio. This allows the ultrasonic diagnostic device 1 to further improve the S / N ratio of the generated ultrasonic images. The operation and processing of the control unit 218 in this case can be easily considered based on the operation and processing of the control unit 218 described above, and therefore a detailed description thereof will be omitted.

[0078] As described above, in the ultrasonic diagnostic device 1 of the embodiment, the control unit 218 detects the maximum value (LNA input maximum value) of the reflected wave signal that may be input to the LNA 2142 included in the detection unit 214, based on the measurement signal that is based on the measurement reflected wave signal output by the measurement unit 216, calculates the maximum gain of the LNA 2142 that allows the detected maximum value to pass (LNA maximum passing gain), and sets this in the LNA 2142. Furthermore, in the ultrasonic diagnostic device 1 of the embodiment, the control unit 218 calculates the maximum value (VGA output maximum value) of the output signal that the VGA 2143 outputs when the output signal of the LNA 2142 when the maximum value of the reflected wave signal is input is passed, calculates the gain of the VGA 2143 at which the maximum value of the VGA amplified signal output by the VGA 2143 becomes the calculated output signal, and offsets (corrects) the gain curve of the VGA 2143. In other words, in the ultrasound diagnostic apparatus 1 of the embodiment, the control unit 218 simulates the reflected wave signal passing through the LNA 2142 and VGA 2143 of the detection unit 214 based on the measurement signal generated by the measurement unit 216, calculates the maximum value of the simulated reflected wave signal, and determines the gains to be set in the LNA 2142 and VGA 2143 based on the calculated maximum value. As a result, the ultrasound diagnostic apparatus 1 of the embodiment maximizes the signal level of the reflected wave signal detected during normal detection operation without saturating it, and converts the detected signal (digital signal) by making full use of the dynamic range of the detection ADC 2146. This allows the examiner to view an ultrasound image with reduced image quality degradation and a maximized S / N ratio, based on the converted signal. Furthermore, in the ultrasound diagnostic apparatus 1 of the embodiment, the control unit 218 monitors the occurrence of saturation in the detection signals of all channels during normal detection operation. If saturation is detected in any of the detection signals, the control unit 218 can notify the examiner to urge them to adjust the gain. As a result, the ultrasound diagnostic apparatus 1 of the embodiment allows the examiner to more appropriately perform the examination. Moreover, the ultrasonic diagnostic apparatus 1 of the embodiment realizes the function of determining the gains to be set in the LNA 2142 and VGA 2143 and the function of monitoring the occurrence of saturation in the detection signal while suppressing an increase in circuit size and power consumption.

[0079] In the ultrasound diagnostic device 1 of the embodiment, the measurement unit 216 is provided for several channels near the center. However, the measurement unit 216 may be provided for, for example, one central channel. In this case, the changeover switch 2162 included in the measurement unit 216 may be configured to connect the input signal line of the measurement AMP 2164 to the output signal line of the TRSW 2141 included in the detection unit 214 of several channels near the center. Then, the control unit 218 may be configured to sequentially switch the output signal line connected to the input signal line by the changeover switch 2162 during the measurement operation for gain adjustment. Even with this configuration, it is possible to set suitable gains for the LNA 2142 and the VGA 2143. The configuration of the measurement unit 216 and the operation and processing of the control unit 218 in this case can be easily understood based on the configuration of the measurement unit 216 and the operation and processing of the control unit 218 described above, and therefore detailed description thereof will be omitted.

[0080] According to at least one of the embodiments described above, the ultrasound diagnostic device (1) has an ultrasound probe (10) that includes a plurality of transducers (12), each of which transmits an ultrasound signal toward a subject using the transducer, and each of which receives a reflected wave signal that is returned after the transmitted ultrasound signal is reflected inside the body of the subject, a plurality of detection units (214) that correspond to the respective transducers and detects the reflected wave signal received by the corresponding transducer, a measurement unit (216) that, when determining the gain of at least one detection unit among the plurality of detection units, is capable of measuring a reflected wave signal with an amplitude greater than that at which at least one detection unit is saturated, and a control unit (218) that calculates the gain based on the reflected wave signal measured by the measurement unit and controls the setting of the gain to the detection unit, thereby making it possible to set an appropriate gain in circuits (at least 2142, 2143) that process the reflected wave signal.

[0081] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0082] 1···Ultrasound diagnostic device, 10···Ultrasound probe, 20···Main unit, 21···Transmitting and receiving circuit, 212···Pulser, 214···Detecting unit, 2141···Transmitting and receiving separation switch (TRSW), 2142···Low noise amplifier circuit (LNA), 2143···Variable gain amplifier circuit (VGA), 2144···Programmable amplifier circuit (PGA), 2145···Low pass filter (LPF), 2146···Detecting (AD converter) ADC, 216···Measurement unit, 2162···Selection switch , 2164···Measurement amplifier circuit (AMP), 2166···Measurement (AD converter) ADC, 218···Control unit, 2181···Signal measurement function, 2182···Maximum value detection function, 2183···Gain calculation function, 2184···Gain control function, 2185···Saturation monitoring function, 22···Signal processing unit, 23···Processing circuit, 24···Memory circuit, 25···Input interface, 26···Output interface, 27···Communication interface, 250···Input device, 260···Display device

Claims

1. an ultrasound probe including a plurality of transducers, each of which transmits an ultrasound signal toward a subject, and each of which receives a reflected wave signal that is returned after being reflected from inside the subject; a plurality of detectors corresponding to the respective transducers and detecting the reflected wave signals received by the corresponding transducers; a measurement unit that measures the reflected wave signal having an amplitude greater than that at which the at least one detection unit is saturated when determining a gain of the at least one detection unit among the plurality of detection units; a control unit that controls a gain setting for the detection unit; Equipped with Each of the detection units includes at least a first amplifier circuit that amplifies the reflected wave signal and outputs a first detection signal; a second amplifier circuit that further amplifies the first detection signal output by the first amplifier circuit and outputs a second detection signal; Equipped with The measurement unit a third amplifier circuit that measures the reflected wave signal, amplifies the signal, and outputs a first measurement signal; a first analog-to-digital converter for converting the first measurement signal into a first digital signal; Equipped with the control unit sets a first gain to the first amplifier circuit and a second gain to the second amplifier circuit, both of which are calculated based on the first digital signal; Ultrasound diagnostic equipment.

2. the first amplifier circuit is a low-noise amplifier circuit, the second amplifier circuit is a variable gain amplifier circuit, the third amplifier circuit is an amplifier circuit that can pass a signal with a larger amplitude than the first amplifier circuit; The ultrasonic diagnostic apparatus according to claim 1 .

3. The control unit a first maximum value of the reflected wave signal is detected based on the first digital signal, and a maximum gain through which the detected first maximum value can pass is defined as the first gain; an output signal when the first maximum value passes through the first amplifier circuit set to the first gain, an output signal is obtained by multiplying the output signal by a gain curve scheduled for the second amplifier circuit to obtain a second maximum value, and a gain at which the second maximum value becomes the maximum value of the second detection signal output by the second amplifier circuit is set as the second gain for correcting the gain curve; The ultrasonic diagnostic apparatus according to claim 2 .

4. The measurement unit a switching circuit that switches the input of the reflected wave signal to the third amplifier circuit, The control unit the switching circuit is controlled so that the reflected wave signal is not input to the third amplifier circuit in a first operation in which the detection unit detects the reflected wave signal, and the reflected wave signal is input to the third amplifier circuit in a second operation in which the detection unit determines the first gain and the second gain. The ultrasonic diagnostic apparatus according to claim 3 .

5. The reflected wave signal is When determining the gain of the detection unit, the ultrasonic signals transmitted by each of the transducers are ultrasonic signals that are reflected by the body of the subject and returned. The ultrasonic diagnostic apparatus according to any one of claims 1 to 4.

6. The measurement unit is provided for each of the detection units corresponding to the plurality of transducers arranged at the center of the ultrasonic probe, among the plurality of transducers. The ultrasonic diagnostic apparatus according to any one of claims 1 to 5.

7. Each of the detection units includes at least a second analog-to-digital converter for converting the detected reflected wave signal into a second digital signal representing the magnitude of the reflected wave signal; the control unit controls the measurement of the reflected wave signal by the measurement unit and the setting of the gain based on a result of monitoring the second digital signals of all the detection units. The ultrasonic diagnostic apparatus according to any one of claims 1 to 6.

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